"The elephant in the room, is the pieces of shaft/bevel gear potentially unrestrained in the TXMSN."
Having looked up into the bottom of an EC225 MGB with the bottom cover removed, I can assure you that when the shaft driving the bevel gear fractures at the weld and drops into the bottom of the sump, there is no way for shaft or gear pieces to be carried up into the other moving bits inside the gearbox. It is a fully enclosed chamber.